Stat comparison
Among the most interesting decisions to make in World of Warcraft are those concerning gear. Should a warrior prefer +Stamina or +Dodge%? Is +heal better or mana/5? Of course there can be no "right" answers to such questions. It's always a matter of "it depends...", but sometimes reasonable upper and lower limits can be found (e.g. 5 mana/5 will for all casters always be better than 10 spi). Another helpful insight is the Item Values article, just to see which relative values Blizzard gives to different stats. Healer mana There are many aspects to the problem how to optimize a healers endurance. Lets look at the various item stats which can affect healer mana and/or efficiency. Intellect Int simply increases the mana pool and spell crit chance. It's the benchmark for the other stats. Spirit When considering spi, it is important to understand how mana regeneration works (see 5 second rule). There are mods which collect the data on how much time is spent inside the 5 second rule, and how much mana each point of spirit regenerated (like Spirit versus Intellect). For "average" combats it's safe to assume that 1 spi = 1 int. Mana/5 At first glance mana/5 is quite similar to spi - it regenerates mana. In combat though mana/5 is usually "better", as a rule of thumb a factor of 3 can be assumed (1 mana/5 = 3 spi) +heal Comparing +heal to the other stats is a little tricky. It is necessary to consider current mana efficiency (HP/mana and HP/time) and its change due to +heal. For any given combat thus the saved amount of mana can be found. The effect of additional +heal becomes less after a certain point, because increasing an already high efficiency yields less of an effect than increasing a low efficiency. The various sources agree that a factor of about 8 is appropriate to convert +heal to mana/5 (1 mana/5 = +8 heal). Spell crit% Similar to +heal, this increases efficiency (with the added problem that crits may easily result in overheal). One percent crit in theory increases total HP healed by 0.5%, which in turn could be translated to an increase of the available mana by the same amount. Summary Reducing all stats to Int leads to the following: 1 Spi = 1 Int 1 Mana/5 = 3 Int +8 heal = 3 Int In longer fights +heal and mana/5 become more important, when grinding spi and int are preferrable. For PvP, Int is probably the most important stat, because PvP encounters tend to be short but intense, and the increased critrate is important there too. A very thorough discussion can be found at WoWHealers Related articles: * Formula:Healers Shields Category:Equipment STR vs AGI Value of Strength The value of strength is different for different classes. *Hunters/Rogues gain 1AP per str, which translates to approximately .07 DPS per Str (1/14). *All other classes gain 2AP per str, which translates to approximately .14 DPS per Str (2/14). Note that this is strictly melee attack power; the calculations for ranged attack power (RAP) are different. Also note that this is base "white" dps, and does not consider changes to other abilities. Value of Agility Agility increases one's white DPS by increasing his chance to critical hit, and the magnitude of this effect is determined by their level and class. *The effect of increasing your critical hit percentage by exactly 1% is the same as increasing your base white DPS by 1%. (Note that *Rogues/Hunters gain 1AP or .07 DPS per AGI. Example: :Imagine a druid does 10dps (strictly white DPS) when you hover over his combat stats. He also has 0% chance to crit. Imagine his weapon swings exactly once a second. So after 100 seconds (100 swings), he will have done 1000 damage. With 1% critical hit chance, ONE of those swings will be for double damage, so he will have 99 swings for 10 damage, and 1 swing for 20 damage, which equals 990 + 20 or 1010 damage, exactly a 1% increase in total DPS. Further if that druid has 1% crit and swung twice every second, he would get 200 swings in 100 seconds, for a total of 198 * 10 damage swings = 1980 + two 20 damage swings, or 2020, exactly a 1% increase in total damage. The only time this is not true is when you take into effect certain damage mitigation effects, which is for a future article. Since AGI increases DPS by a percentage of your current DPS, and STR increases DPS arithmetically (same DPS per STR, no matter how high DPS is), we can see that there is a point where the two formulas will cross and it will be more beneficial to add 1 point of AGI instead of 1 point of STR in future equipment upgrades. ---- Equilibrium Point At this DPS point, the DPS gained by 1 STR and 1 AGI are equal. Past this point 1 AGI will always yield more DPS. The formula to find the equilibrium point is: :DpsPerStr = CritPerAgi * X + DpsPerAgi where *X is the equilibrium point in DPS. *DpsPerStr = .075 for Rogues/melee Hunters and .15 for all other classes. *CritPerAgi = Critical Hit percentage in decimal form gained by 1 AGI point, changes based on level and class, explanation below. *DpsPerAgi = .075 for Rogues/Hunters/Cat druids, 0 for other classes *'These constants are subject to alteration by talents. (such as Heart of the Wild)' *'Because DpsPerStr and DpsPerAgi are equal for rogues and hunters, the equilibrium point is zero. There is never a point where a rogue or hunter should take a point of STR over a point of AGI.' For the rest of us. Consider a level 27 NE druid (not in cat form). :DpsPerStr = .15 :CritPerAgi = .001 (that is, 1 agi = 0.1% crit chance) :DpsPerAgi = 0 :.15 = .001(x) + 0 :x = 150 Until the shown DPS (what is shown when you hover your mouse over your damage display in the character menu) is equal to 150 it is MORE beneficial from a white DPS standpoint to put 1 point into STR than it is to put one point into AGI. After the equilibrium it is always better to put points into AGI. Now consider for a moment that same druid in cat form. :DpsPerStr = .15 :CritPerAgi = .001 (that is, 1 agi = 0.1% crit chance) :DpsPerAgi = .075 :.15 = .001(x) + .075 :.075 = .001(x) :x = 75 Again, remember that these constants are subject to alteration by talents. Calculating Critical Hit per AGI By de-equipping an item with +AGI (don't use a weapon) we can determine CritPerAgi. *CritPerAgi = Change in crit percent / change in agility Steps #Hover your mouse over your AGI and write down the percentage, we will call it Y for now. #Remove a piece of equipment with some AGI on it (not your weapon to keep it easy). #Hover your mouse over your AGI and write down the percentage again, we will it Z. #Y - Z = Change in crit percent. #Divide by the number of AGI on the equipment you removed = critical hit percentage per AGI. #Divide by 100 to determine CritPerAgi Example: :I hover AGI and have a 7.27 crit percentage, remove a 4 AGI item and I have a 6.87 crit percentage. :7.27 - 6.87 = .4 :.4 / 4 AGI removed = .1 crit percentage per AGI, or a CritPerAgi of .001. Note: It is important to hover over AGI to determine your current critical hit percentage because the critical hit percentage shown in your character window is a the sum of many factors including current weapon skill, + crit items etc. If you do the calculations based on the change in that number you will be off in your math, you must do the calculations based purely off the change in the AGI derived critical hit percentage. In the prior paragraph where we determined Current DPS, you will want to use the shown critical hit percentage to determine current DPS because you are interested in the current amount of damage you do. Determining Current DPS By determining our current DPS we can figure out how close we are to reaching that equilibrium point and therefore help to guide is in future equipment upgrades. * current white DPS is equal to Shown DPS * (1 + critical hit percentage). Therefore on the druid above. :Shown DPS is 24.1 and critical hit in caster form is 6.14%. :White DPS = 24.1 * (1.0614) = 25.57974. Plugging it into the equilibrium equation we deduce that at this point it is without question more beneficial to increase STR than AGI when evaluating based on DPS. ---- Importance of the Equilibrium Point When evaluating the data in this way we are able to determine what would actually make our character better, with the goal of removing the "wow" factor that critical hits sometimes give us. The goal is the most damage possible, and often to reach that point the solution is not AGI, it is STR. Also, by looking at the data in this way we can see that Rogues and Hunters reach the equilibrium point twice as fast, because they gain only .075 DPS per str. Even then it is clear that some people are placing points into AGI when their current DPS is too low to have an effect. A huge percentage increase of a tiny number is meaningless. This is where weapon DPS is also crucial, the more powerful the weapon the closer to the equilibrium point you are. Dodge/Armor Effect on Equilibrium Point AGI increases armor and dodge as well. Sometimes one may choose to sacrifice DPS for a reduction in damage taken. In situations where damage is being dealt and recieved, (PvP, PvE, not neccessarily Raids), It is arguable that *Reducing one's damage taken by 1% is equivalent to increasing one's damage given by 1%. With that principle we can refine the Equilibrium point equation to. *DpsPerStr = (CritPerAgi + DodgePerAgi) * X where *X equals the equilibrium point in DPS. *DpsPerStr = .075 for Rogues/Hunters and .15 for all other classes. *CritPerAgi = Critical Hit percentage in decimal form gained by 1 AGI point, changes based on level and class. *DodgePerAgi = Dodge percentage in decimal form gained by 1 AGI point, changes based on level and class. This point is up for debate and depends on the circumstance. In PvP where you are taking damage and dealing damage I believe this calculation is justified, but when PURE DPS is the goal, then one cannot include their damage mitigation into the formula, and must use the original formula presented earlier. I did not include the effect of AGI on armor simply because I believe that increasing damage is more important than reducing damage taken, and I believe the slight increase in armor is enough to safely assert that 1% dodge is equivalent to 1%dps, because the increase in armor balances the loss in DPS. (this section may be expanded in the future) Future data points In order to elaborate on this topic we will need more critical hit per AGI data points. With enough data points, we might be able to determine a formula for determining the critical hit per AGI per class. Using the above methods you can always calculate your current class and levels equilibrium point. If future authors can submit additional data points we can begin to really create a functional knowledge of the relationship between AGI, STR and DPS. ---- Data points Format Level Race Class - Crit percent per Agi | Dodge percent per agi | DPS equilibrium | DPS equilibrium w/mitigation *27 NE Druid - .1% | .1675% | DPS eq = 150 | DPS eq w/mit 56.0747 *10 ORC Warrior - .1925% | .1625% | DPS eq = 77.92 | DPS eq w/mit 42.25 *21 ORC Shaman - .106667% | .106667% | DPS eq = 140.625 | DPS eq w/mit 70.3125 *23 TAU Shaman - .105% | .105% | DPS eq = 142.85 | DPS eq w/mit 71.42 *60 ORC Shaman - .05125% | .05125% | DPS eq = 292.68 | DPS eq w/mit 146.34 One thing is certainly evident, the effect of AGI on dodge and crit is widely different depending on class/level and possibly the amount of AGI. I do not believe the amount of AGI determines the effect gained from it, often the UI will round in the numbers shown which can yield differences in the calculation. When I took my 27 NE druid at 64 agi and removed equipment piece by piece recording the change in crit percentage there were a few removals which differed VERY slightly from the .1% (.0998%) I recorded earlier, but after a few removals it would return to the .1%. Interesting inferences from the data: *Shaman dodge per agi = crit per agi. *Warrior crit per agi > dodge per agi. *Druid crit per agi < dodge per agi. (hopefully many more of these inferences will emerge as data points increase).